signal loss with wireless network

Hi, please help me
i am new to this forum, i have WRT54G router on mixed mode and has been configured to run wireless and wire network i have also set it to permit only one mac address which is for the laptop.
I have 4 pcs on the wired network and 1 laptop on the wireless network.
The problem is that on the wireless connection it keeps disconnecting and reconnection about 6 or 7 times every couple of hours.
is this just something that happens on wireless networks or is there somthing wrong.